From 5f20152f01febf4ffd9572a8ab3e980a4660ef69 Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Mon, 3 Jul 2023 06:42:20 -0700
Subject: [3.12] gh-106359: Fix corner case bugs in Argument Clinic converter
 parser (GH-106361) (#106364)

gh-106359: Fix corner case bugs in Argument Clinic converter parser (GH-106361)

DSLParser.parse_converter() could return unusable kwdicts in some rare cases

(cherry picked from commit 0da4c883cf4185efe27b711c3e0a1e6e94397610)

Co-authored-by: Erlend E. Aasland <erlend@python.org>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
---
 Lib/test/test_clinic.py                                  | 16 ++++++++++++++++
 .../2023-07-03-14-06-19.gh-issue-106359.RfJuR0.rst       |  2 ++
 Tools/clinic/clinic.py                                   | 16 +++++++++-------
 3 files changed, 27 insertions(+), 7 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Tools-Demos/2023-07-03-14-06-19.gh-issue-106359.RfJuR0.rst

diff --git a/Lib/test/test_clinic.py b/Lib/test/test_clinic.py
index bea7303..76a06df 100644
--- a/Lib/test/test_clinic.py
+++ b/Lib/test/test_clinic.py
@@ -813,6 +813,22 @@ Annotations must be either a name, a function call, or a string.
         )
         self.assertEqual(s, expected_failure_message)
 
+    def test_kwarg_splats_disallowed_in_function_call_annotations(self):
+        expected_error_msg = (
+            "Error on line 0:\n"
+            "Cannot use a kwarg splat in a function-call annotation\n"
+        )
+        dataset = (
+            'module fo\nfo.barbaz\n   o: bool(**{None: "bang!"})',
+            'module fo\nfo.barbaz -> bool(**{None: "bang!"})',
+            'module fo\nfo.barbaz -> bool(**{"bang": 42})',
+            'module fo\nfo.barbaz\n   o: bool(**{"bang": None})',
+        )
+        for fn in dataset:
+            with self.subTest(fn=fn):
+                out = self.parse_function_should_fail(fn)
+                self.assertEqual(out, expected_error_msg)
+
     def test_unused_param(self):
         block = self.parse("""
             module foo
diff --git a/Misc/NEWS.d/next/Tools-Demos/2023-07-03-14-06-19.gh-issue-106359.RfJuR0.rst b/Misc/NEWS.d/next/Tools-Demos/2023-07-03-14-06-19.gh-issue-106359.RfJuR0.rst
new file mode 100644
index 0000000..600c265
--- /dev/null
+++ b/Misc/NEWS.d/next/Tools-Demos/2023-07-03-14-06-19.gh-issue-106359.RfJuR0.rst
@@ -0,0 +1,2 @@
+Argument Clinic now explicitly forbids "kwarg splats" in function calls used as
+annotations.
diff --git a/Tools/clinic/clinic.py b/Tools/clinic/clinic.py
index d182e5e..d67479c 100755
--- a/Tools/clinic/clinic.py
+++ b/Tools/clinic/clinic.py
@@ -4289,6 +4289,7 @@ class IndentStack:
 
 
 StateKeeper = Callable[[str | None], None]
+ConverterArgs = dict[str, Any]
 
 class DSLParser:
     def __init__(self, clinic: Clinic) -> None:
@@ -5016,10 +5017,10 @@ class DSLParser:
         key = f"{parameter_name}_as_{c_name}" if c_name else parameter_name
         self.function.parameters[key] = p
 
-    KwargDict = dict[str | None, Any]
-
     @staticmethod
-    def parse_converter(annotation: ast.expr | None) -> tuple[str, bool, KwargDict]:
+    def parse_converter(
+            annotation: ast.expr | None
+    ) -> tuple[str, bool, ConverterArgs]:
         match annotation:
             case ast.Constant(value=str() as value):
                 return value, True, {}
@@ -5027,10 +5028,11 @@ class DSLParser:
                 return name, False, {}
             case ast.Call(func=ast.Name(name)):
                 symbols = globals()
-                kwargs = {
-                    node.arg: eval_ast_expr(node.value, symbols)
-                    for node in annotation.keywords
-                }
+                kwargs: ConverterArgs = {}
+                for node in annotation.keywords:
+                    if not isinstance(node.arg, str):
+                        fail("Cannot use a kwarg splat in a function-call annotation")
+                    kwargs[node.arg] = eval_ast_expr(node.value, symbols)
                 return name, False, kwargs
             case _:
                 fail(
-- 
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